Papers by Keyword: Extrusion Process

Abstract: In most cases, recycled plastics include lots of impurities that can not be separated in operation steps of separation and washing. Normally, these impurities should be filtrated in extrusion process with filter plate and single or twin screw extruder. In extrusion process, it is easily for impurities to block the holes of filter plate. So how to improve the performance of self-cleaning can be regarded as a very important requirement for design of filter equipment. Based on FEM simulation, this paper discusses mechanism of filter plate’s blocking, the pressure distribution and deformation of two direct flow filtrations. Specially, a side stream filtration including how to clean itself has been introduced.

Abstract: The main objectives of this paper is to find the way for solving the problems of aluminum extrusion process, and improve the mechanical properties of the products through a smart design, modelling and simulation of this process by using finite element method (FEM). For the purpose to model a (2D) two dimensions warm aluminum extrusion process, ABAQUS software was used to set up the finite element simulation. The main parameters which have major effects on this process like extrusion stresses, temperature, and die geometry, i.e. extrusion radius, were taken into consideration. Aluminum alloy (Al-2014) was used as the billet material, with 40 mm diameter and 75 mm length. It is important to preheat the billet from the beginning to a specific temperature, and then pressurizes it into the die. This process is an isothermal process with an extrusion ratio of 3.3. Subsequently, the optimized algorithm for these extrusion parameters was suggested based on the simulation results. The results suggest that the large die angle needs a less extrusion load than the small die angle. In all die geometry used, the deformation of aluminum billet, which caused by shearing and compression stresses, happened in a small sectional area, i.e., bearing area. The results also showed that the values of these stresses can increase or decrease depends on the die entrance angle and the die bearing length. To avoid the effects of these stresses on die dimensions; the hardness, material selection, and geometry should be well calculated.

Abstract: Changes in selected physical properties of thermoplastic composites during and after exposure materials to ultraviolet radiation and freeze were investigated. The matrix of composite was homopolymer polypropylene. The fillers were talcum, chalk, short glass fiber in mass fraction 10 to 50% and montmorillonite by fraction only 4%. The composites were mixed in plasticizing system of extruder. The length of plasticizing system and number of grooves in feed zone was changed. The samples were exposed for two months to UV and -20°C. The short ageing influenced on hardness, microhardness and Raman spectroscopy of composites. The SEM showed how extrusion process affected the homogeneity of composites structure.

Abstract: This paper reviews the chain of aluminum Direct Recycling process. Direct Recycling is one of intelligent process to recycle the aluminum waste. The current method for recycle waste aluminum, was affect on the environmental issues. This paper focus on the aluminum waste from machining process, also called chips produced from turning and milling process. From chip collected, next compaction process are compressed to the certain amount pressure for consolidating the materials. Lastly to produce a new material, the process is extrusion process. The most important issue to get a quality of a product is, how to control the pressure during both of process. During this process also available in hot and cold condition. From review, it was that cold compaction process more popular implemented compared to hot compaction. Then almost researchers applied hot extrusion it is because to cover sintering process.

Abstract: According to the profile section of transport equipment, the wide and hollow AZ31 magnesium alloy profiles was self-designed. Extrusion molding performance of the profiles, the law of microstructure and mechanical properties were studied when billets pretreatment and extrusion temperature were changed. The conclusions are as follows: (1) The grains of AZ31 profiles extruded by pre-extrusion billet are smaller and the strength is better, its maximum tensile strength is 280MPa. (2) Other processes being equal, the grains of AZ31 profiles are smaller and strength is higher, but the plastic is bad, when the extrusion temperature is 300°C. However, both strength and ductility of AZ31 profiles are better, when the extrusion temperature is 350°C. (3) Wide and Hollow AZ31 profiles perform significant heterogeneity and anisotropic characteristics on mechanical properties.

Abstract: According to the defects of powder metallurgy superalloy, especially the influence and damage of inclusions on properties of disk, the deviation between nondestructive testing and metallographic testing of inclusions in FGH96 alloy isothermal forging disk was investigated. Meanwhile, the types and deformation mechanism of inclusions were studied. The results showed that the buried depth tested by metallographic detection was less 67-180μm than nondestructive testing. The size of inclusions with metallographic detection was less about 18-50μm than nondestructive testing. The major types of inclusions in practical disk were Al₂O₃ and Al₂O₃-SiO₂, the inclusions run through several grains, no matter Al₂O₃ or Al₂O₃-SiO₂. The Al₂O₃ inclusion and matrix was purely mechanical bonding, but the Al₂O₃-SiO₂ had reaction zone. There was remarkable effect of extrusion process on crushing and dispersing Al₂O₃ inclusion, but which was unremarkable for Al₂O₃-SiO₂.

Abstract: The microstructure and tensile properties of the as-cast and as-extruded Mg-12Li-1Zn-xSn (x=1, 3, 5, 8, wt.%) alloys were investigated. The alloys are mainly composed of β-Li phase, Mg₂Sn phase. With the increase of Sn content, the microstructure of as-cast alloys is refined. After extrusion processing, grain size is obviously refined, and the Mg2Sn phase is broken into tiny particles. The elevated-temperature tensile behavior of the alloy was investigated at 373~523k under the strain rate of 1×10^-2~1.7×10^-4s^-1. The results indicate addition of Sn can improve the strength and plasticity, when the content of Sn is 5.0 wt.%, the as-extruded alloy possesses good superplasticity, which obtains the maximum elongation of 134.4% under a low strain rate of 1.0×10^-3s^-1 at 523K.

Abstract: The extrusion process can produce composites with high-density matrix and fibre packing, low permeability and fibre matrix bond strengthening. This process is also compatible with the use of vegetable fibres as raw materials in the production of cost-effective construction elements such as ceiling panels. Sugar cane bagasse fibres (SCF), one of the largest cellulosic agroindustrial by-products of sugar and alcohol industry available in Brazil, are a renewable resource usually used as a biomass fuel for the boilers. The remaining bagasse is still a source of contamination to the environment, so there is a great interest on exploiting novel applications to sugar cane bagasse fibres. In this work, the effect of SCF on extruded cementitious composite performance was evaluated. Three different contents of SCF were considered, using cellulose pulp as secondary micro-reinforcement to improve the resistance to the appearance of microcracks. Composites were prepared using a laboratory Auger extruder with vacuum chamber and were tested after 28 days of water curing and after 200 accelerated ageing cycles. Modulus of rupture (MOR) and Tenacity (TE) of extruded composites were assessed by four point bending test. Water absorption and apparent volume were determined by water immersion. Microstructure behavior was evaluated by mercury intrusion porosimetry and scanning electron microscopy (SEM). Results indicated that the introduction of larger fibres increased tenacity (TE) at 28 days and favored a higher amount of macropores (0.1 to 1 mm); SEM observations confirmed that fibre degradation occurred after 200 cycles.

Abstract: Prepare poly butylene terephthalate (PBT)/multi-walled carbon nanotubes (MWNTs) composites through the method of melt blending. Then use low-cost single screw extruder to conduct experimental research and analysis on the extrusion test sample of PBT/MWNTs composites of different proportions under the conditions of changing the extrusion temperature, rate, cooling mode and so on. As a result, the process parameters of the better extrusion temperature, critical extrusion rate, and high-gloss molding etc. to reinforce the electrical properties of composites under low-cost experiment condition have been obtained. The experiment results also indicate that with the increasing of the MWNTs content, the surface resistivity of the composites shows a declining trend.

Abstract: Based on the high-tin wear-resisting Cu-Sn-Pb-Ni Alloy which the tin content is 9~11%, the inverse extrusion plastic forming experiments in the temperature range of 800°C~ 950°C were completed. The density and hardness of alloy castings were tested and the casting mircostructure was analyzed after plastic forming, which compared with the properties and microstructures of alloy casting prepared by traditional melt casting. The results show that the density and hardness of Cu-Sn-Pb-Ni alloy casting prepared by traditional melt casting are 8.8893g/cm³ and 116HB separately, the density and hardness has increased after inverse extrusion plastic forming in different tempretures, especially at 900°C the density and hardness reached the maximum values, 9.0409g/cm³ and 139HB respectively. Compared with the as-cast microstructure is mainly obvious dendrite structure which are α solid solution and eutectoid（α+δ）, The as-extruded of alloy exhibit better propertief and its grain are obviously refined and densed. Within the range of experiments, the best inverse extrusion plastic forming tempreture is at 900°C.